1. Field of the Invention
This invention relates to a method and apparatus for moving objects within three-dimensional space. More specifically, the invention relates to a traveling highline aerial cable rail system.
2. Description of the Related Art
The controlled movement of heavy objects through large volumes of three-dimensional space has given rise to inventions that fail to satisfactorily achieve the full spectrum of speed, load bearing, volume serviced, extensibility, maintainability and platform stability. A “highline” system is a system based on an elevated cable or rope, along which objects are transported.
According to the invention disclosed in U.S. Pat. No. 5,020,443, a highline invention is described which can haul heavy loads, but does not provide quick movement in the X-axis, since large tractors supporting the ends of the highline must be physically relocated. The tension on the highline can vary dramatically depending on obstacles that lie within the path of the vehicles, which can cause the Z-axis of the payload to vary greatly during motion along the X-axis.
In U.S. Pat. No. 6,145,679, an invention is disclosed in which balloons keep the highline aloft, however, one end of the invention is rigid, which would inhibit moving a rescue container or piece of equipment, or log payload to a defined location outside of the pie-shaped space that the invention services. Also, high winds would plague the system as the high surface area of the balloons would render controlled movement inconceivable. Servicing a group of containers at the lower point of the highline requires movement of the containers since the highline is fixed at the lower end.
In U.S. Pat. No. 5,585,707, an invention is disclosed in which a robot or person can be readily moved within three-dimensional space. Although this invention does not use a highline, it is still able to traverse three-dimensional space. The payload is limited and the support structure is small scale. If the structure were to be scaled up, obstacles such as trees or buildings would inhibit the motion of the payload through a path between two points defined within the cube, since there are so many wires required to practice the invention. Also, the invention would not appear to allow the Z-axis to vary beneath the cube, and the size of the cube support structure to service a large volume of space would be extremely expensive to build on the scale required.
In U.S. Pat. No. 5,568,189, an invention is disclosed for moving cameras in three-dimensional space. The problems with the '189 invention are many when scale of the system is enlarged. FIG. 4 clearly shows how the two parallel highline cables sag inward, when the payload is in the middle of the X, Y space. Since the invention does not use strong rails to support the Y-axis rope, the weight bearing of the invention is dependent upon the strength of the building or structure in which it is mounted and the springs in its weight bearing X-axis connectors. The motors for the various axes are mounted up in the rigging, which would require multiple extremely long power cables to traverse the volume of space along with the payload if the invention were modified for outdoor use. The power cables would total over 3 times the length of the longest axis to drive the far X-axis motor, the Y-axis motor and the Z-axis motor. Mounting heavy motors high in the rigging presents a major safety issue given that suspension lines can break. The size of the motors limits the payload that can be carried, and further limits the speed at which the payload can be carried. The invention is also fixed in size, not allowing for modular addition of X travel, or increasing the Y or Z-axis travel without mounting the structure in a bigger studio or building a bigger hanger.